SRS Labs SIM928 Manuale operativo
Operation and Service Manual
Isolated Voltage Source
SIM928
Stanford Research Systems
Revision 2.0 •August 25, 2006
Certification
Stanford Research Systems certifies that this product met its published specifications at the time
of shipment.
Warranty
This Stanford Research Systems product is warranted against defects in materials and workman-
ship for a period of one (1) year from the date of shipment.
Service
For warranty service or repair, this product must be returned to a Stanford Research Systems
authorized service facility. Contact Stanford Research Systems or an authorized representative
before returning this product for repair.
Information in this document is subject to change without notice.
Copyright c
Stanford Research Systems, Inc., 2005, 2006. All rights reserved.
Stanford Research Systems, Inc.
1290–D Reamwood Avenue
Sunnyvale, CA 94089 USA
Phone: (408) 744-9040 •Fax: (408) 744-9049
Printed in U.S.A. Document number 9-01593-903
SIM928 Isolated Voltage Source
Contents
General Information iii
Safety and Preparation for Use . . . . . . . . . . . . . . . . iii
Symbols ............................. iv
Notation ............................. v
Specifications .......................... vi
1 Getting Started 1 – 1
1.1 Introduction to the Instrument . . . . . . . . . . . . . 1 – 2
1.2 Front-Panel Operation . . . . . . . . . . . . . . . . . . 1 – 2
1.3 SIMInterface........................ 1–6
2 Remote Operation 2 – 1
2.1 Index of Common Commands . . . . . . . . . . . . . . 2 – 2
2.2 Alphabetic List of Commands . . . . . . . . . . . . . . 2 – 4
2.3 Introduction ........................ 2–6
2.4 Commands......................... 2–7
2.5 StatusModel........................ 2–17
3 Circuitry 3 – 1
3.1 Circuit Description . . . . . . . . . . . . . . . . . . . . 3 – 2
3.2 PartsList.......................... 3–7
3.3 Schematic Diagrams . . . . . . . . . . . . . . . . . . . 3 – 7
i
ii Contents
SIM928 Isolated Voltage Source
General Information
The SIM928 Isolated Voltage Source, part of Stanford Research Sys-
tems’ Small Instrumentation Modules family, is a low-noise pro-
grammable voltage source intended for sensor biasing and other
demanding, low-power applications. Dual, auto-switching inter-
nal nickel-metal-hydride batteries provide continuous uninterrupted
operation at the isolated output, which can deliver up to ±20 V bias
at up to ±10 mA current load.
Safety and Preparation for Use
The front-panel binding post outputs (+and −) are isolated from
the Earth, the power-line-outlet ground, and the metal chassis of
the module. No dangerous voltages are generated by the SIM928.
However, if a dangerous voltage is externally applied to the module,
WARNING it may be present on (either) binding post connector, the chassis, or
the SIM interface connector, and may cause injury or death.
Do not exceed ±40 V to the Earth at either binding post terminal.
The SIM928 ships from the factory with the internal battery pack
installed and ready for operation. Do not install substitute parts or
perform any unauthorized modifications to this instrument.
The SIM928 is a single-wide module designed to be used inside the
SIM900 Mainframe. Do not turn on the power until the module is
completely inserted into the mainframe and locked in place.
iii
iv General Information
Symbols you may Find on SRS Products
Symbol Description
Alternating current
Caution - risk of electric shock
Frame or chassis terminal
Caution - refer to accompanying documents
Earth (ground) terminal
Battery
Fuse
On (supply)
Off (supply)
SIM928 Isolated Voltage Source
General Information v
Notation
The following notation will be used throughout this manual.
A warning means that injury or death is possible if the instructions
WARNING are not obeyed.
A caution means that damage to the instrument or other equipment
CAUTION is possible.
Typesetting conventions used in this manual are:
•Front-panel buttons are set as [Button];
[Adjust ] is shorthand for “[Adjust ] & [Adjust ]”.
•Front-panel indicators are set as Overload.
•Remote command names are set as *IDN?.
•Literal text other than command names is set as OFF.
Remote command examples will all be set in monospaced font. In
these examples, data sent by the host computer to the SIM928 are set
as straight teletype font, while responses received by the host
computer from the SIM928 are set as slanted teletype font.
SIM928 Isolated Voltage Source
vi General Information
Specifications
Performance Characteristics
Min Typ Max Units
Output Output range −20 +20 V
Floating output −40 +40 V (common mode to ground)
Noise 10 µVrms, 1 kHz BW
Settable resolution 1 mV
Display resolution 1 mV, |V|<1.999 V
10 mV, |V|<19.99 V
Max. output current −10 +10 mA (before dropout)
Short circuit current ±15 mA
Short circuit duration indefinite
Batteries Number of batteries 2 1 operating, 1 charging/standby
Chemistry Nickel metal hydride
Charge time 5 h
Discharge time 12 h (10 mA load)
Lifetime 1000 charge cycles, 2 yr shelf life
Battery switching Automatic, when active battery is fully discharged
Switchover glitch <1 mV for <1 ms
Battery charge override Allows manual switching of batteries. Triggered when
[Battery Override] is held for 5 s or more. Only armed
when standby battery is in ready state
Operating Temperature 0 40 ◦C
Power −15,+5,+24 V DC
Supply current 250 mA (+5 V)
40 mA (−15,+24 V)
General Characteristics
Interface Serial (RS-232) through SIM interface
Connectors Banana binding posts (+,−, and chassis ground)
DB–15 (male) SIM interface
Weight 3 lbs
Dimensions 1.500 W×3.600 H×7.000 D
SIM928 Isolated Voltage Source
1 Getting Started
This chapter gives you the necessary information to get started
quickly with the SIM928 Isolated Voltage Source.
In This Chapter
1.1 Introduction to the Instrument . . . . . . . . . . . . 1 – 2
1.1.1 Overview .................... 1–2
1.1.2 Power-on State . . . . . . . . . . . . . . . . . 1 – 2
1.2 Front-Panel Operation . . . . . . . . . . . . . . . . . 1 – 2
1.2.1 Adjust ...................... 1–3
1.2.2 Battery...................... 1–4
1.2.3 Output...................... 1–5
1.3 SIMInterface ...................... 1–6
1.3.1 SIM interface connector . . . . . . . . . . . . 1 – 6
1.3.2 Direct interfacing . . . . . . . . . . . . . . . . 1 – 7
1–1
1–2 Getting Started
1.1 Introduction to the Instrument
The SIM928 Isolated Voltage Source is ideally suited for applications
demanding flexibility and low-noise from a programmable voltage
source.
1.1.1 Overview
The basic function of the SIM928 is to generate a user-specified volt-
age, between −20 V and +20 V, between the +and −front-panel
terminals. The architecture of the SIM928 uses an internal battery
to power the output stage. This provides an ideal voltage source,
free of power-supply ripple. Two independent batteries are used;
while one is powering the output circuitry, the second is either be-
ing recharged or held in standby. When the output battery nears
its fully-discharged state, the standby battery is seamlessly switched
into the output circuit, and the depleted battery switched to the inter-
nal charger. With this arrangement, essentially continuous isolated
bias voltage is available to the user.
Note that, although the output stage is energized by internal storage
batteries, the control circuitry is powered externally (typically, by the
SIM900 Mainframe). Absent any external power, the SIM928 will be
off.
1.1.2 Power-on State
The SIM928 stores its operation state (programmed voltage and
on/offconfiguration) in non-volatile memory. At power-on, the
SIM928 will return to its previous configuration after a brief system
check and initialization.
The power-on system check includes a brief test of both internal bat-
teries. If either battery appears fully discharged, it will be switched
onto the internal charger circuit; if both batteries appear discharged
(as can occur after an extended storage period), the SIM928 will not be
able to turn on the output stage. In this case, you should allow aboutfirst use after extended storage
5–6 hours of powered operation to bring the first battery up to full
charge, at which time it will switch to the On state and begin charging
the second battery. This period can be shortened by power-cycling
the SIM900 Mainframe, which will cause the SIM928 to re-initiate it’s
power-on checks. Note that at least 1–2 hours should be allowed to
provide a sufficient partial charge for reasonable operation.
1.2 Front-Panel Operation
The front panel of the SIM928(see Figure 1.1) provides a simple op-
erator interface.
SIM928 Isolated Voltage Source
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